The unprecedented number of death threats against President Obama, a rise in racist hate groups, and a new wave of antigovernment fervor threaten to overwhelm the US Secret Service, according to government officials and reports, raising new questions about the 144-year-old agency’s overall mission.

The Secret Service is tracking a far broader range of possible threats to the nation’s leaders, the officials said, even as it also investigates financial crimes such as counterfeiting as part of its original mandate.

The new demands are leading some officials, both inside and outside the agency, to raise the possibility of the service curtailing or dropping its role in fighting financial crime to focus more on protecting leaders and their families from assassination attempts and thwarting terrorist plots aimed at high-profile events.

“If there were an evaluation of the service’s two missions, it might be determined that it is ineffective . . . to conduct its protection mission and investigate financial crimes,’’ according to a inter nal report issued in August by the Congressional Research Service.

The report, which was provided to the Globe, said such a review should look at how money and staff are allocated, and whether some of the agency’s functions and workers should be transferred to the Treasury Department.